Grain drying apparatus



Oct. 12, 1943. A. B. ossoop 2,331,720

GRAIN DRYING APPARATUS Filed NOV. 5, 1941 3 Sheets-Sheet l Oct. 12, 1943. A. B. OSGOOD 2,331,720

' GRAIN DRYING APPARATUS,

Filed Nov. 3, 1941 s Sheets-'-She et, s

entirety by the numeral l0.

Patented Oct. 12, 1943 My present invention relates to drying apparatus and providescertain improvements therein.

which especially adapt the apparatus for the treatment of corn, wheat, and similar grains. Generally stated, the invention consists of the novel" devices, combinations of devices, and arrangement of parts hereinafter described and defined in the claims.

. Corn, wheat, and'similar grains very frequently and, in fact, usually contain more moisture than desired for storage or milling operations. In fact, some grains containing more than approximately 18% of moisture will not keep well instorage. t

The drying is produced' by a hot dry air blast.

. The grain is primarily subjected'to the hot air blast by passing the same through a drier such, for example, as that known as the Direct Heat Drier through which the hot blast is caused to pass. The air blast acting on the grain as it passes through the drier willipick up and carry off dust, dirt, and the flakes or particles'of the hull loosened from-the grainanddelivers the same to cyclone dust collectors. These cyclone'dust collectors are placed in a closedchamber within which the air pressure is keptabove atmospheric pressure, by the air blast; and hence, this cham ber may be properly designated as a plenumchamber. This chamber is preferablyprovided with a hopper-like bottom and its walls are preferably well insulatedsoas to keep the dust collectors from low temperatures and the dust-laden air at relatively high temperature during the dust-collecting and separating actions.

'A commercial embodiment of the invention is illustrated in the accompanying drawings where- I in like characters indicate like parts throughout the several views. I

Referring to the drawings:

Fig. 1 is a view, partly in side elevation and partly in vertical section, taken on the line l-'l of Fig. 2, and with some parts broken away illus trating the improved apparatus;

Fig. 2 is a transverse vertical section taken on the line 2-2 of Fig. 1;

Fig. 3 is a horizontal section taken approximately on the line 3-3 of Fig. 1;

Fig. 4 is a fragmentary view chiefly in elevation but with some parts sectioned on the line ll4 of Fig. 1; and

Fig. 5 is a fragmentary section taken on the line 5-5 of Fig. 4.

The various parts of the apparatus are preferably enclosed within a housing indicated as an This housing, as

' air ports:23.- The ports 22open into the receiving.

shown, is divided into two compartments Jiil and I2 between which is a partition 'l3 having large air passages 14.; Located in the compartmentis a fan or blower (as shown of the sirocco type) and involving a motor-driven rotary head l5 and a casing I6. Casinggl6 has an axialair inlet I1" and the outlet of said casing is in the form of a flaring shell l8 that affords a main air trunk 19 that delivers to thevarious ports. l4 and through i the latter to the chamber or compartment l2.

Extending "vertically and horizontally of the air trunk I9 is a drier casing 20 that is preferably a rectangular sheet metal structure Located with in the drier casing or shell 20" isa multiplicity of inverted U-shaped bafiles'2l which; as willhere inafter benoted, perform the dual function of deflectors for the corner grain and for the-air and also serve as open bottom air-conductors or conduits.

Imthefront wall of the drier casing '20" are air I ports 22 and in the rearwall thereof; are similar ends of certainbf the inverted U-shaped baiiles 2i and the ports 23 open or lead from the delivery ends of others of said battles. However; no one of the baffles has a port at both ends. As best indicated in Fig. 4, the receiving ports 22 open into the receiving ends of the one horizontal row of bafiies and the discharge ports 23 lead from the-delivery ends of other or adjacent horizontal rows. The importance 'of'this' relative arrangement will be made more'apparent in the descripf tion of the'operation s The drier casing Zilis preferably formed with a hopperlike bottom adapted to be opened and closed by a gate or valve 24';

Locatedwithin' the chamber or compartment 12 is'a multiplicity of cyclone dust collectors 25 having tangential airintake ports 26 and tangential air discharge spouts -21, which latter pref f erablyopen outside of the compartment i2.

These cyclone dust collectors ar of well-known or any suitable type and they are arranged in an upper series and in a lower series with corresponding upper andlower collectors in verti cal axial alignment.

lectors have hopper-like bottoms with long tubelike discharge necks 29 that extend axially down V The lower dust collectors are provided with hopper-like bottoms terminat ing' in discharge-necks 23,'whi1e the upper 001- All of the necks or tubes 28 andtubes.

The compartment l2 serves as a large settling chamber and is provided with a hopper-like bottom 32 that terminates in an open top discharge trough 33 in which works a spiral conveyor 34. The two spiral conveyors 3| and 34 will be power-driven through suitable transmission mechanism including, as shown, a sprocket chain 35 that runs over sprockets 36 and 31, respectively, on the projecting shafts of the conveyors 3| and 34. The discharge spouts or tubes 30 and 33 deliver to a common depending discharge spout 38.

To protect the mechanism within the compartment I2 from excessively low temperatures in cold weather, said chamber is shown as lined with insulating material indicated at 39. The corn or grain to be dried or treated may bedelivered to the drier in any suitable-wa but, as

shown, is arranged to be thus delivered through a supply pipe 40 extended from a suitable source of supply.

The air-intake pipe I! to the fan or blower, in practice, wil1'- lead from a source of hot dry air. In the operation of this apparatus, the hot air blast will carry the dust, lint, or foreign materials that have been loosened from the grain through and from the drier and into the plenum chamber l2, and from thence through the several cyclone dust collectors. The warm air thus delivered into chamber l2will surround and keep theexteriors of the dust collectors warm seas to prevent condensation of the moisture until after it has passed through the dust collectors. Some of the dust or foreign materials will be precipitated onto the hopper-like bottom 32 and from thence intothe discharge troughs 33. The materials discharged by gravity from the dust collectors will, of course, be delivered into the spout 30. The spout 30 and the trough v33 will. by the conveyors 3| and 34, be discharged into the common delivery spout 34 without opening the said trough and spout to the atmosphere.

Further comments This pre-heated air is passed at high temperature and relatively low humidity through the grain column losing some of its original temperature and picking up moisture from the grain being dried. This operation also tends to dry the hull or outside shell of the grain, thereby 5 making it brittle and much of this hull is picked up by the air and carried to the discharge side of the drier column. The spent air now contains a relatively lower temperature but a much higher relative humidity together with a considerable amount of light chat! and hull. .The object of this is to removethis objectionable chafi or hull particles from the spent air and due to the relatively high humidity, it is necessary to separate the dust before any considerable loss in temperature causes a condensation and steam in the collector apparatus. In order to accomplish this, the plenum chamber, which houses the dust collectors, is insulated to prevent drop in temperature and the air is passed around the outside surface or surfaces of the collectors before entering the collector inlet to further prevent condensation in the interior of the dust collectors. tained at a pressure greater than atmospheric, it is also necessary to provide means for removing the dust from the cone outlets by some means that will prevent a difference in pressure between the cone outlets and the atmosphere. This is accomplished by a. screw conveyor connected to the dust outlets removing the separated dust and discharging it outside the plenum chamber. The object of the hopper bottom in the plenum chamber with its open top screw conveyor i to remove the heavier dust particles which settle in the plenum chamber itself and passing the air through the chamber before entering the dust collector. With this arrangement of equipment, condensation does not take place until the spent air is discharged from the outlets of collectors through the wall of plenum chamber to the outside. The collectors are, therefore, handling air of high relative humidity but without water being condensed to interfere with the normal separation of dust in the collectors.

It is often desirable to cool the corn or grain after it has been dried and that may be readily accomplished by providing a drier and air delivery device such, for example, as that already illustrated, and employing a drier casing 20 which may be a duplicate of the casing 28 and its ports and conduits. In Fig. 1 this lower casing'ifl' is shown as positioned as above indicated.

What I claim is:

1. In a drying apparatus, a plenum chamber, an upright drier having vertical passages for the gravity feed of grain or the like downward therethrough, and having transverse air passages, an air trunk spanning one side of said drier. said drier at its opposite side opening into said plenum chamber, means for producing an air blast in said air trunk and thence through said drier and the grain falling therethrough and from thence into said plenum chamber, and a dust collector of the cyclone type, having an outer shell located Within said plenum chamber, said shell having an inlet leading from the interior 'of said plenum chamber and having an outlet through, and having transverse air passages, an air trunk spanning one side of said drier, said drier at its opposite side opening into said plenum chamber, means for producing an air blast in said air trunk and thence through said drier and the grain falling therethrough and from thence into said plenum chamber, and a dust collector of the cyclone type, having an outer shell located within said plenum chamber, said shell having an inlet leading from the interior of said plenum chamber and having an outlet leading to the exterior of said plenum chamber, said plemun chamber having a hopper-like bottom with a discharge passage leading therefrom and the outer shell of said dust collector having a hopper-like bottom with a discharge passage opening into the lower portion of said plenum chamber.

ARTHUR B. OSGOOD.

Since the plenum chamber is main- 

